[China Glass Network] Introduction
Glass building is a rich and wide-ranging architectural form, which mainly refers to buildings that use glass in large areas. Due to the fashion, lightness and transparency of glass buildings, the development and application of glass buildings has reached an unprecedented height since the 1970s. However, the widespread use of glass curtain walls has also brought many problems, such as: a large amount of energy consumption, severe light pollution, large carbon dioxide emissions and line of sight interference. Among these many problems, the large consumption of energy, especially in the cold regions, has been a major problem plaguing the development of glass buildings. If the problem of energy waste is not solved, the development of glass buildings in cold regions will be greatly limited, and it can even be said that it will be stagnant.
1. Factors affecting the energy efficiency of glass buildings
(1) Building orientation: The orientation of the glass building is important. Note: (1) Solar radiation can be obtained as much as possible in winter; (2) Solar radiation should be minimized in summer; (3) Natural ventilation should be fully utilized in summer, and cold air should be directly blown in winter. Attack.
(2) Plane layout: For the glass building, from the plane layout analysis, it should be partitioned, that is, the main room and the large space are arranged in the south, and the large window or the glass curtain wall is opened, and the traffic core and the auxiliary room are arranged in the north or the east. Towards, should open a small window or a glass curtain wall.
(3) Plane shape: For glass buildings, we consider that the south facade is the benefit surface, and the other three sides are regarded as the heat loss surface. By comparing with the square plane, we can conclude that the glass building plane should be arranged according to the east-west axis. The side length ratio is preferably 1:1.5 to 1:4.
(4) Body shape coefficient: The body shape coefficient refers to the ratio of the external surface area of ​​the building in contact with the outdoor atmosphere and the building volume enclosed by it. The larger the body shape coefficient, the larger the heat dissipation area shared by the unit building space, and the more energy consumption. From the point of view of energy saving, the rational design should be based on the principle that the radiant heat absorbed by the south facing glass surface should be larger, as much as possible than the heat dissipated outward.
(5) Surface area factor (ratio of other surface area of ​​the building to the south direction area): For the glass building to obtain more sunshine radiation and reduce energy consumption, the smaller the surface area coefficient, the better. Therefore, in terms of energy saving, I think that the rectangular shape with the long axis toward the east is better, the square is second, and the rectangular structure with the long axis toward the north and south is less energy-efficient.
2, energy-saving glass analysis
For glass buildings, the technology and use of glass is directly related to the energy consumption of buildings. The solar radiation transmittance and heat transfer coefficient of ordinary glass are very high. The building with ordinary glass as the window has many solar radiant heat in the summer, and the air conditioning load is large. In the winter, there are many heats lost in the outdoor, and the heating load is high. In order to improve this situation, different types of energy-saving glass are needed. There are coated glass, insulating glass, heat absorbing glass and the like.
(1) Heat-reflecting coated glass: It is a method of applying a film on the surface of the glass by physical or chemical deposition. Since the film has special photothermal properties, that is, reflecting solar radiant energy, it becomes an energy-saving glass. This glass mainly has the following characteristics: (1) weakening the passage of ultraviolet rays; (2) better visible light transmittance ratio and reflectance; (3) smaller shielding coefficient and solar radiation heat transmittance; (4) lower Heat transfer coefficient (insulation performance); (5) obvious regional adaptability; (6) rich and varied reflection color.
(2) Low-radiation coated glass: It is a low-radiation film coated on the surface of the glass, which has high reflection ability to infrared radiation, and also means that any energy contained in the film is radiated as radiation. The main characteristic of this kind of glass is that the transmittance of visible light in the visible light range of 0.3~0.75μm is more than 80%, which is enough to ensure indoor brightness and reduce lighting energy consumption. It also has high transmission in the near-infrared band of 0.75-2.5μm. Than, the radiant energy of sunlight can enter a larger part of the room. The 2.5~30μm far-infrared wave emitted by indoor objects has a reflection ratio of more than 80%, so that the indoor heat energy is transmitted to the outside less, which can keep the indoor light bright and reduce the indoor heat load to a certain extent, especially It is almost completely impermeable to the far-infrared rays generated by the radiation of objects below 2000oC. It is this that has prompted many people to suggest that low-emissivity glass is “warm glassâ€.
(3) Insulating glass: The insulating glass reduces the convection and conduction heat transfer of the glass by forming a certain thickness between the two sheets of glass and restricting the flow of air or other gas layers. Therefore, it has a good thermal insulation capability. Insulating glass is a glass with very good energy-saving effect, not only because of its own energy-saving effect, but also by using hollow glass to combine various energy-saving types of glass, so that a large energy-saving effect can be achieved within a reasonable cost range.
In summary, under normal circumstances: in winter, the glass with better energy-saving effect is low-emissivity glass, followed by heat-reflecting hollow, white glass hollow and heat-reflecting single piece, while white glass single-piece glass has poor energy-saving effect. In summer, the energy-saving effect is better low-emissivity glass, followed by heat-reflecting glass, monolithic heat reflection and white glass hollow, while white glass monolithic glass has poor energy-saving effect. For the whole year, the energy-saving effect is better low-emissivity glass, followed by heat-reflecting hollow, single-piece heat reflection, white glass hollow and white glass single piece. Therefore, for cold regions, it is better to use low-emission hollow coated glass as far as energy saving is concerned.
3. Energy-saving technical measures
Reducing the heat loss of glass building envelopes in cold regions is the key to energy saving in glass buildings. The heat loss of the enclosure structure is reduced, that is, the heat transfer heat consumption and the cold air penetration heat consumption of the enclosure structure are reduced. The specific measures are as follows:
(1) Selection of energy-saving glass: For all-glass curtain wall construction, the glass type should be determined according to the location of the glass. The north-south direction should adopt different structural measures and energy-saving glass to achieve better energy-saving effects. In cold regions, the south facing glass curtain wall should use low-radiation insulating glass with moderate shading coefficient or heat-reflecting insulating glass, while the north direction is recommended to use high-transparent insulating glass or low-radiation insulating glass, so that better energy saving can be achieved. effect.
(2) Combination of energy-saving glass: Different types of energy-saving glass have different performance advantages. Only based on the geographical, climate, function and other conditions of the building, based on the full understanding of various glass technical characteristics, they can be effectively combined. In order to fully realize the energy saving benefits. Generally, the combination of energy-saving glass includes: heat-reflecting glass and ordinary single-piece glass, heat-absorbing glass and ordinary single-piece glass, low-emissivity glass and ordinary single-piece glass, low-emissivity glass and heat-reflecting glass (endothermic glass). From the perspective of energy saving, the glass combination suitable for cold regions is: hollow glass combined with low-emissivity glass and heat-reflecting glass, low-radiation insulating glass, heat-reflecting insulating glass, and ordinary insulating glass.
(3) Use of shading technology: Shading usually has the form of internal shading, external shading, green shading and respirable curtain wall system. The use of shading measures is not only a necessary means for energy-saving design of glass curtain wall buildings, but also a necessary means for the architectural design of standard high-rise glass curtain wall buildings.
(4) Use of natural ventilation: Natural ventilation is mainly due to the pressure difference between the indoor and outdoor sides, so air circulation occurs. The forces that create pressure are wind and air lift, which form wind pressure and hot pressure, respectively. In the application of natural ventilation means, we must pay attention to the following aspects: (1) unified consideration of building design; (2) careful opening of windows in upper buildings; (3) consideration of natural ventilation and mechanical ventilation.
4 Conclusion
Glass building is a highly complex form of function, technology and aesthetics. Its energy-saving design is a multi-functional system design that is coordinated and cooperated by various technical experts in terms of energy concept, content composition and work process. The big difference between it and the energy saving of ordinary buildings is that it is impossible to solve the single problem, while ignoring the one-sidedness and negative accompanying effects (such as the greenhouse effect). Only by paying attention to the integration of technology and correctly balancing the comprehensive relationship among the various determinants, is the fundamental way to better organize energy-saving technical measures, thereby making use of lighting, ventilation and solar energy flexibly, and exerting comprehensive energy-saving effects.
Our company, located in Baiyun, Guangzhou, is a company with 20 years of experience in hat production. We specialize in customizing various kinds of hats, which can be customized according to drawings, and support OEM and ODM. Winter thermal caps are also a kind of hats that our company is good at developing, such as Doudou knitted hats, Lei Feng hats, outdoor hunting hats, berets, etc. If you need, please contact us at any time
Beanie hat,Balaclava,Beret
Guangzhou Ace Headwear Manufacturing Co., Ltd. , https://www.custom-cap-hat.com